从2.6.24到2.6.33：Linux内核十个版本性能对比

从2008年1月底至今，Linux Kernel系统内核已经先后升级了十次，版本号也从2.6.24
上升到2.6.33
，并且下个版本2.6.34也已进入开发阶段。今天我们就看看过去两年内这十个版本在性能上有何差异。
测试平台是一套工作站系统，硬件配置包括AMD Opteron 2384 2.7GHz四核心处理器(“上海”)、泰安Thunder n3600B S2927主板(NVIDIA nForce 3600PRO芯片组)、4GB DDR2 ECC Reg内存、希捷ST3300622AS 300GB硬盘、ATI FirePro V8700显卡，软件上采用Ubuntu 8.04.4 LTS 64位操作系统，组件有GNOME 2.22.3、X.Org Server 1.4.0.90、GCC 4.2.4、EXT3。
Linux Kernel 2.6.24-2.6.33的每个版本都从Ubuntu PPA源上获取，而且均为64位版本。除了替换内核之外，系统其他设置均保持默认。
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Apache Benchmark(静态网页服务)：2.6.33成绩大幅提升，但事实最早的2.6.24版反而才是好的，之后八个版本都差得很多，最新版终于基本正常了。
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PostgreSQL pgbench(每秒钟TPC-B交易数)：2.6.30的成绩比上个版本骤然提升了多达770％，但之后2.6.32迅速下滑，最新的2.6.33却又完全不如2.6.30之前的六个版本了。
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7-Zip Compression(文件压缩速度)：不同版本有所波动，最新的2.6.33成了赢家，这才是我们最希望看到的。
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LZMA Compression(256MB文件压缩)：十个版本几乎没什么区别。
[url=/uploadfile/2010/0302/20100302094308738.png]screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.alt='Click here to open new window\nCTRL+Mouse wheel to zoom in/out';}" onmouseover="if(this.width>screen.width*0.7) {this.resized=true; this.width=screen.width*0.7; this.style.cursor='hand'; this.alt='Click here to open new window\nCTRL+Mouse wheel to zoom in/out';}" onclick="if(!this.resized) {return true;} else {window.open('http://pub.chinaunix.net//uploadfile/2010/0302/20100302094308146.png');}" onmousewheel="return imgzoom(this);" alt="" />[/url]
Bork File Encrypter(文件加密时间)：经过一番起伏之后，2.6.33又回到了当初2.6.24的水平，而之前一个版本2.6.32还是最快的。
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PostMark(磁盘性能)：和PostgreSQL测试结果惊人地相似，2.6.30-2.6.32三个版本性能异常突出，最新版里却又消失了。

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Dbench(单个客户)：PostgreSQL、PostMark的故事再次上演，而且2.6.33的性能成了最差的，落后幅度也很大。
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Dbench(12个客户)：运行多个Dbench客户端之后情况又不同泐，2.6.30-2.6.32同样有明显改进，2.6.33则呈现井喷之势，不过也可能和系统内存缓存有关。
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FFmpeg(AVI视频转NTSC VCD)：所有版本都差不多。
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C-Ray光线追踪引擎：完全没区别。
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Bullet物理引擎：只有第一个版本2.6.24稍差一些，之后一直非常稳定。
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NAS Parallel Benchmark：美国航空航天局(NASA)用于评估并行超级计算机性能的测试程序，所有版本都没什么不同。
小结：
经过两年多的发展，Linux Kernel系统内核在稳定性和功能上都有了翻天覆地的变化，而这里我们只是考察了它们在部分情况下的性能，特别是和工作站应用相关的。
总的来说，十个版本在性能上基本保持稳定，但也有一些例外，最明显的就是PostgreSQL、PostMark的起起伏伏，很可能和EXT3文件系统已经廉颇老矣有关，不过EXT4系统目前的主要工作仍是保证稳定性和可靠性，性能也有待提升。
新版内核也有不少时候表现更好一些，尤其是Apache Web服务器性能，终于解决了困扰将近两年的性能问题。7-Zip压缩性能也不错。